While wall forming systems have been in use for many years, a recent development in this industry is in the use of expanded polystyrene panels as forms for the poured concrete walls. After the concrete has hardened, the panels are left in place on the walls to serve as permanent insulation.
This new wall system utilizes a system of "blocks", each block comprised of a pair of polystyrene panels connected in parallel spaced-apart alignment by a series of rigid plastic ties between the panels. Each panel has a series of T-shaped slots along its upper and lower edges, into which the T-shaped end of the plastic ties would be inserted to "lock" the panels into a block. The panels further utilize a corrugated or striated innerface, and a smooth outer face. The upper, lower and side edges all have tongue and groove elements so that a series of blocks can be stacked and locked together to create forms for a wall. Concrete is then poured between the panels, the hardened concrete adhering to the panels and to the corrugations on the inside surfaces of the panels. Since the T-shaped ends of the ties do not extend completely through the panels, a smooth panel surface would face the exterior of the wall and could be finished as desired. The panels thereby provide a form for pouring the concrete as well as an insulated wall once the concrete has hardened.
While this insulation panel system has proved quite successful, the system is limited by the fact that the panels must be left in place on the concrete wall. This system is not capable of use on those occasions where an exposed concrete surface is desired. Thus it was necessary to revert to the older methods of form boards, steel bracing within the concrete, and exterior bracing to hold the form boards in the appropriate alignment. Such a system is cumbersome, utilizes heavy materials, and is difficult to utilize to produce accurately aligned walls.
A further problem with the insulated panel system of the prior art is in the expense of manufacturing a specific length of tie for every desired width of wall to be poured. While the ties themselves are relatively inexpensive, the contractor would quite often end up with a large volume of extra ties in many different sizes, and would be forced to carry many sizes of such ties to every site at which concrete was to be poured.
The prior art insulated panel wall system also utilizes only a single thickness panel in the system. Thus, any additional insulation that may be desired after the wall is prepared, requires an additional construction expense, and in some cases requires the construction of another "wall" in order to obtain an appropriate surface for the desired finish.
The ties utilized in the prior art insulated panel system also limited the construction technique and possibilities for the panel system. In those instances where a conduit or pipe is intended to be incorporated within a wall to be newly poured, the "blocks" of panels and ties cannot be utilized to surround the pipe. A special assembly would be necessary in such a situation.
It is therefore a general object of the present invention to provide an improved tie for use in panel-type forms for poured concrete walls.
Another object is to provide a tie which is adjustable in length to accommodate a variety of wall thicknesses.
Another object of the present invention is to provide a tie which has adjustable-length panel-holding ends, to accommodate a variety of panel thicknesses.
Still another object is to provide a two-piece tie with identical, connectable halves.
A further object of the present invention is to provide a two-piece tie which is connectable in a variety of lengths.
Yet a further object of the present invention is to provide a tie which may be utilized in combination with prior art insulated panels as well as new types of panels utilized in poured concrete wall forms.
Another object of the present invention is to provide an adjustable tie which is inexpensive to manufacture, simple in design, and refined in appearance.
These and other objects will be apparent to those skilled in the art.